Bacterial wound infection is one of the most common nosocomial infections.The unnecessary employment of antibiotics led to raising the growth of antibioticresistant bacteria. Accordingly, alternative armaments capable of accelerating wound healing along with bactericidal effects are urgently needed. Considering this, we fabricated chitosan (CS)/polyethylene oxide (PEO) nanofibers armed with antibacterial silver and zinc oxide nanoparticles. The nanocomposites exhibited a high antioxidant effect and antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Besides, based on the results of the cell viability assays, the optimum concentration of ZnONPs and AgNPs in the nanofibrous mats is 0.2% w/v and 0.08% w/v respectively and had no cytotoxicity on fibroblast cells. The scaffold also showed good blood compatibility according to the effects of coagulation time. As well as significant fibroblast migration and proliferation on the wound margin, according to wound-healing assay. All in all, the developed biocompatible, antioxidant, and antibacterial Ag-ZnO NPs incorporated CS/PEO nanofibrous mats showed their potential as an effective wound dressing.antibacterial, antioxidant, chitosan/polyethylene oxide nanofibers, electrospun, silver nanoparticles, wound healing, zinc oxide nanoparticles | INTRODUCTIONWound infection is a common and unsolved issue in preventing wound healing. Any kind of wound on the skin is susceptible to the accumulation of infectious bacteria. 1 With the spread of antibiotic-resistant bacteria, employing antibiotics to prevent and treat wound infections is inefficient.In addition, it imposes extra costs on the patient and society. Consequently, alternative materials are pivotal to combat pathogens. 2,3

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Some microorganisms were isolated from copper mines and recognized as copper resistant. Genotyping was conducted using 16srDNA sequencing. The bioaccumulation and extracellular nanoparticle biosynthesis were conducted for Bacillus cereus under the varying copper concentration range using mathematical modeling. AFM, TEM, and particle size analyzer were used for the characterization and the nanoparticle analyses. Cell toxicity was assayed against human cells. Maximum biosorption capacities were 1200 or 2500 μg g−1 when 0.5 or 1 mg ml−1 CuSO4 was provided for the bacillus cells, respectively. In contrast, extracellular bioreduction kinetics revealed a threefold change from ≈250 to 700 μg ml−1 in the same treatment conditions. No time shift was recorded for reaching the maximum extra/intra nano-copper synthesis in both copper concentration models. Bacillus cereus synthesized nano-coppers within a range of 80–150 nm. Metal nanoparticles were at least twofold less toxic than their copper sulfate on the human cells and T47D was the most resistant cell against nano-coppers. The toxicity effects were dose-dependent, time-dependent, and also organism- and heavy metal type-dependent. The results revealed that the copper-resistant Bacillus cereus is a robust and high-throughput microorganism for intracellular and extracellular nano-copper biosynthesis.